It is the important line of defense against hackers. If your Windows password is indeed attacked finally or nevertheless you lost Windows password, you can try out windows password reset tool I mentioned above.
One thing I would like to add that Windows Password can be easily hacked by Ophcrack
or using DOS (who is expert in DOS can easily do this)! So, if someone needs real security for his/her PC then better to switch to other OS like Red Hat or Fedora etc.